The dietary needs of older dogs will change, so give them the appropriate food. Generally, they need small but nutritious food, more protein and less salt and phosphorus. Choose high-quality foods that are easy to digest and stay hydrated...
How to make your old dog’s old age better 
See your veterinarian regularly:Senior dogs need regular visits to the veterinarian to ensure good health. This includes a physical exam, blood tests, and eye and ear tests.
Eat well:The dietary needs of older dogs will change, so give them the appropriate food. Generally, they need small but nutritious food, more protein and less salt and phosphorus. Choose high-quality foods that are easy to digest and stay hydrated.
Control your weight:Avoid overweight older dogs as this can be detrimental to their health. Check your weight regularly and adjust your diet and exercise.
Moderate exercise:Even though older dogs may not have the same energy as their younger counterparts, they still need moderate amounts of exercise. This helps keep your joints flexible and your heart healthy.
Protect joints and bones:Older dogs are prone to joint problems, so be careful to protect them. Provide a soft bed to avoid too much movement and protect their joints.
Provide psychological stimulation:Older dogs may feel lonely, so provide plenty of companionship and activity. Interact with them, play with them, and give them love and attention.
Medical treatment:Depending on the health of your senior dog, some medical treatments, such as painkillers, physical therapy, etc., may be needed to help relieve pain and discomfort.
All in all, senior dogs need special care to keep them healthy and happy in their later years. Regular veterinary visits, a proper diet, moderate exercise and providing psychological stimulation are keys to ensuring their health and happiness.